Stretching instrument



FIG. 1 is a top plan view of the stretching instrument, showing the new design;

FIG. 2 is a bottom plan view thereof;

FIG. 3 is a left-side elevational view thereof;

FIG. 4 is a right-side elevational view thereof;

FIG. 5 is a front elevational view thereof;

FIG. 6 is a rear elevational view thereof;

FIG. 7 is a rear, right-side, top perspective view thereof;

FIG. 8 is a front, bottom, right-side perspective view thereof;

FIG. 9 is a front, left-side, top perspective view thereof; and,

FIG. 10 is a rear, left-side, bottom perspective view thereof.

The broken lines depict parts of the stretching instrument that form no part of the claimed design. 

CLAIM The ornamental design for a stretching instrument, as shown and described. 